SIOG9330 - Settlement by agreement: offers: non-standard offers must preserve HMRC rights
The standard forms of instalment offer found in the Appendices of the Enquiry Manual contain clauses ensuring that not only can HMRC enforce on the full amount of the contract in the event of non-payment, together with interest, but they can also repudiate the agreement and proceed by assessments and determinations if wished.
The more unusual and specialised an offer the greater the risk of a deficiency arising when enforcement is attempted. This makes it essential that these offers should fully preserve HMRC’s right to set the offer aside and proceed on an alternative basis.